The aim of this investigation is to study the effect of piperidine on the central neurons of the snail Helix pomatia which have been identified as cardioregulatory motoneurons or interneurons and simultaneously to study the role of piperidine in the chemical regulation of the neuronal network controlling cardiac activity. In these experiments, the heart-cardiac nerve-subesophageal ganglionic preparation of Helix pomatia can be used with simultaneous recording of: (a) the intracellular activity of two identified central neurons; (b) the extracellular activity of the cardiac nerve; and (c) heart contractions (or ECG). A possible liberation of piperidine as a result of stimulation of cardiac activity via the cardiac nerve will also be studied. These experiments represent fundamental steps in a sequence of investigations aimed at establishing the role of piperidine in the CNS. BIBLIOGRAPHIC REFERENCES: Fairman, K., E. Giacobini and V. Chiappinelli, Developmental variations of tyrosine hydroxylase and acetylcholinesterase in embryonic and posthatching chicken sympathetic ganglia. Brain Research, 1976. 102. 301-312. Giacobini, E., K. Fairman, V. Chiappinelli and L. Yurkewicz, The effect of reserpine on the development of tyrosine hydroxylase in chick sympathetic ganglia. Abstr. 7th Ann. Meeting Am. Soc. Neurochem. (Vancouver, Canada) 1976.